T-Mobile said no financial data or social security numbers were involved, but personal information such as account numbers, email addresses, billing addresses and phone numbers may have been exposed.

"We take the security of your information very seriously and have a number of safeguards in place to protect your personal information from unauthorized access," T-Mobile said in a statement. "We truly regret that this incident occurred and are so sorry for any inconvenience this has caused you."

T-Mobile did not disclose how many customers were impacted. Citing a company spokesperson, Vice reports the breach impacted roughly 3 percent of its 77 million customers, which is approximately 2.3 million customers.

T-Mobile could not be immediately reached for comment. In a statement, T-Mobile said all affected customers have been or will be soon notified.

This is not the first time T-Mobile has suffered a breach of user data. In 2015, the wireless carrier said the personal records of 15 million people were compromised through a breach at Experian, which processed the company's credit applications.